Method of producing an irridescent pattern on the surface of a sheet or other object and sheets or objects having patterned surface produced by this method

ABSTRACT

An irridescent surface pattern comprising an array of deformations superimposed on an array of dots marked on an impressionable light-reflecting surface, the spacing between the dots and the spacing between the deformations differing by a small percentage. In one embodiment the dots are produced by half-tone printing on the foil of a foil-laminated sheet of paper and the deformations are produced by embossing the foil with a half-tone plate made of triacetate sheet material using a screen size different to the screen size used by the plate for printing the dots.

United States Patent [191 Mallard [451 July 31,1973

[ METHOD OF PRODUCING AN IRRIDESCENT PATTERN ON THE SURFACE OF A sum OR OTHER OBJECT AND sHEETs OR OBJECTS HAVING PATTERNED SURFACE PRODUCED BY THIS METHOD [75] Inventor: John Mallard, Welwyn, England [73] Assignee: FJ. Warren Limited, Ware Hertfordshire, England [22] Filed: July 15, 1971 [21] Appl. No.2 163,109

[30] Foreign Application Priority Data July 16, 1970 Great Britain 34,599/70 [S2] U.S. Cl 350/109, 350/320, 350/321, 264/1, 264/132 [51] Int. Cl. G02b 5/12 [58] Field of Search 3 /97l09, 167, 320, 321; 264/1, 132

[56] References Cited UNITED STATES PATENTS 6/1907 Deeks 264/132 3,533,690 10/1970 DeMontebello 350/35 3,564,268 2/1971 Bayne 356/71 2,130,256 9/1938 Wilson 350/109 OTHER PUBLICATIONS R. McTier, Distortion Printing & Vacuum Forming of Thermoplastic Sheet, July 1962, S.P.E. Journal, pps. 741-745.

Primary Examiner-David Schonberg Assistant Examiner-Michael J. Tokar AttorneyKemon, Palmer & Estabrook [5 7] ABSTRACT An irridescent surface pattern comprising an array of deformations superimposed on an array of dots marked on an impressionable light-reflecting surface, the spacing between the dots and the spacing between the deformations difiering by a small percentage. In one embodiment the dots are produced by half-tone printing on the foil of a foil-laminated sheet of paper and the deformations are produced by embossing the foil with a half-tone plate made of triacetate sheet material using a screen size different to the screen size used by the plate for printing the dots.

11 Claims, 4 Drawing Figures PAIEM QJULIHIQIS 3 749,471

SHEET 2 OF 2 HMf- CHANGf HALF- TO/Vf A SCREEN TONE PRINT/N6 SIZE EMBOSS/NG METHOD OF PRODUCING AN IRRIDESCENT PATTERN ON THE SURFACE OF A SHEET OR OTHER OBJECT AND SHEETS OR OBJECTS HAVING PATTERNED SURFACE PRODUCED BY THIS METHOD This invention relates to a method of producing an irridescent decorative pattern on the surface of a sheet or other object and to decorated sheets or other objects having patterned surfaces produced by this method.

The type of irridescent decorative pattern with which the present invention is concerned is a surface pattern, different parts of which will reflect light at different angles respectively, these angles of reflection being adapted to undergo changes in response to changes in the angle of incidence of the light impinging on the patterned surface.

The present invention provides a method of producing an irridescent surface pattern comprising the steps of marking an impressionable, light-reflecting surface with a pattern of spaced dots and of deforming the said surface with a pattern of spaced depressions, the spacing of the depressions and the spacing of the dots differing by not less than 1% and by not more than 10% of the larger spacing.

The present invention also provides a sheet or other object bearing an irridescent surface pattern comprising a light-reflecting surface marked with a pattern of spaced dots and deformed with a pattern of spaced depressions, in which the spacing of the depressions and the spacing of the dots differ by not less than 1% and by not more than 10% of the larger spacing.

A preferred form of the method according to this invention will now be described, with reference to the accompanying drawings, in which:

FIG. 1 is a large scale, diagrammatic representation of a small portion of an irridescent pattern,

FIG. 2 is a cross section of part of a foil laminated sheet of paper bearing the pattern of FIG. 1, and

FIG. 3 is a diagrammatic view of a cylinder printing machine, and

FIG. 4 is a block-diagram summarising the method of producing the pattern.

The pattern in FIG. 1 consists of a rectangular array of dots 1 superimposed on a rectangular array of depressions 2. The effect of a depression overlapping a dot has been represented by light cross-hatching 3; this representation is, however, diagrammatic and of necessity fails to show the parallax effect caused by the bottom of the depressions being below the plane of the surface.

The percentage difference between the spacing of the dots and the spacing of the depressions can be clearly seen from the length 4 (10X the spacing of the dots) and the length 5 (X the spacing of the depressions) to be of the order of 5% of the larger spacing. This difference in spacing has been used in the drawing for the sake of clarity but the preferred difference is of the order of 3%, whilst the preferred spacing for decorating a sheet of paper is less than l/lOOth of an inch.

In the method as applied to the production of an irridescent decorative pattern on a foil-laminated sheet of paper, the sheet is first printed with a pattern of dots by means of an ordinary letter-press block using a halftone 133 screen. A half-tone plate is then produced which has a surface pattern of raised dots such that the number per inch of these last-mentioned dots is 3% greater or 3% less than the number per inch of the dots printed on the sheet. Next, a triacetate sheet bearing an inverted half-tone plate is produced from the said halftone plate with the aid of a solvent and a pair of rollers. Then, after about 2 hours have passed, the said plate and the triacetate sheet are peeled apart, the triacetate sheet now bearing an inversion of the said plate with raised projections corresponding to the cavities in the said plate. Referring now to FIG. 3, this triacetate sheet 10 is stuck, e.g., by means of adhesive tape 12, on the flat bed 11 of a cylinder printing machine generally indicated as 15 and the printing machine is operated, without ink, to emboss the required number of patterned sheets 8.

If the required finished product is a picture with only the background pattern as described above, the foregound areas 14 of the picture are blanked out during the production of the patterned background and the foreground of the picture is reproduced on the blanked out area by a conventional printing process.

A cross-section of the pattern as applied to a foillaminated paper sheet 8 is shown in FIG. 2. A sheet of foil 6 on a backing of paper 7 is marked with ink dots l and is deformed with depressions 2. As in FIG. 1 the dots 1 are at a wider spacing than the depressions 2. The block diagram of FIG. 4 summarises the steps used in the production of an irridescent pattern on a foillaminated sheet of paper.

What I claim is:

l. A method of producing an irridescent pattern upon a light-reflecting surface which comprises:

A. marking an impressionable light-reflecting surface with a pattern of dots at a first spacing without substantially permanently deforming said surface,

B. providing a plate bearing raised projections in a pattern that substantially duplicates said pattern of dots except that the linear spacing in any direction of said raised projections differs from said first spacing by not less than 1% and not more than 10%, and

C. embossing the marked surface resulting from step A" with a pattern of deformations corresponding to said pattern of raised projections by pressing said plate against the marked surfurace.

2. The method of claim 1 wherein said marking is done by printing the pattern of dots on the foil of a foillaminated sheet of paper.

3. The method of claim 1 wherein said marking is carried out by means of half-tone printing.

4. The method of claim 1 including the additional step of blanking out parts of said surface during the production of said irridescent pattern.

5. The method of claim 1 wherein said plate is a halftone plate having a surface pattern of raised dots of the same size as said marked dots, said raised dots being 3% greater or 3% less in their number per inch than the number per inch of said marked dots.

6. An irridescent decorative article bearing a patterned light-reflecting surface wherein said surface is:

A. marked with a pattern of dots spaced at a first spacing,

B. embossed with a pattern of deformations of substantially the same size as said dots, said pattern of deformations being substantially a duplicate of the pattern of dots except that the spacing of said deformations differs from said first spacing by not less than 1% and not more than 10%.

distance for the article.

110. An article of claim 9 wherein the spacing of said deformations is less than 0.0l inch.

111. An article of claim 6 wherein the combination of dots and deformations form regions of contrast that present an irridescent printed picture to a viewer of the article. 

1. A method of producing an irridescent pattern upon a lightreflecting surface which comprises: A. marking an impressionable light-reflecting surface with a pattern of dots at a first spacing without substantially permanently deforming said surface, B. providing a plate bearing raised projections in a pattern that substantially duplicates said pattern of dots except that the linear spacing in any direction of said raised projections differs from said first spacing by not less than 1% and not more than 10%, and C. embossing the marked surface resulting from step ''''A'''' with a pattern of deformations corresponding to said pattern of raised projections by pressing said plate against the marked surfurace.
 2. The method of claim 1 wherein said marking is done by printing the pattern of dots on the foil of a foil-laminated sheet of paper.
 3. The method of claim 1 wherein said marking is carried out by means of half-tone printing.
 4. The method of claim 1 including the additional step of blanking out parts of said surface during the production of said irridescent pattern.
 5. The method of claim 1 wherein said plate is a half-tone plate having a surface pattern of raised dots of the same size as said marked dots, said raised dots being 3% greater or 3% less in their number per inch than the number per inch of said marked dots.
 6. An irridescent decorative article bearing a patterned light-reflecting surface wherein said surface is: A. marked with a pattern of dots spaced at a first spacing, B. embossed with a pattern of deformations of substantially the same size as said dots, said pattern of deformations being substantially a duplicate of the pattern of dots except that the spacing of said deformations differs from said first spacing by not less than 1% and not more than 10%.
 7. An article of claim 6 wherein said dots of the marked pattern are dots of a half-tone print.
 8. An article of claim 7 wherein said deformations correspond to the printing elements of a half-tone printing plate.
 9. An article of claim 6 wherein said dots and deformations are of such small size they are not individually resolved when the article is viewed at a normal viewing distance for the article.
 10. An article of claim 9 wherein the spacing of said deformations is less than 0.01 inch.
 11. An article of claim 6 wherein the combination of dots and deformations form regions of contrast that present an irridescent printed picture to a viewer of the article. 